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how to test saft nicd

Posted: Wed Jul 20, 2011 8:50 pm
by tipidave1
Is there a definitive test protocol that can determine the likely health of a cell? The range on my berlingo has been getting worse over recent months :( I would like to be able to test some 'condition un-known' potential replacement cells. Other than putting them under load and obseving any drop in voltage and subsequent recovery is there a more scientific method of determining thier likely condition? All advice gratefully received.
:D

Re: how to test saft nicd

Posted: Wed Jul 20, 2011 9:55 pm
by ChrisB
The scientific way is to load them with a known load and measure the hours they take to discharge.

In theory the Safts can sustain 33amps for 3hrs from fully charged according to this spec sheet

http://www.evdl.org/docs/stmuk.pdf

So a discharge rig that has a load of a couple of hundred watts should do the job, if the battery say dies after 1.5hrs then you could say its only got 50% of its capacity and so on.

One issue could be is trying to charge it back up or making sure its fully charged in the first place, but then if you time the charge and the rate as it goes in then it "should" be OK although I'm not sure how the best way to water it doing this unless you follow the spec sheet I suppose, along with cooling, although as long as you dont discharge it too hard or charge it hard then you may get away with just having some water in the jacket itself :?

Anyone else got any ideas ?

ChrisB

Re: how to test saft nicd

Posted: Tue Aug 30, 2011 7:00 am
by arsharpe
Hi,

I have an automatic electronic load that can test upto 40A, 800W & 80V.

Although it is supposed to be a fully protected unit it had to be replaced, so I am a little reluctant to lend it out.

My wife works in Hamble so should be able to pick them up.

How many have you got ?

Regards,
Rob

Re: how to test saft nicd

Posted: Tue Aug 30, 2011 8:27 am
by timpootle
viewtopic.php?f=6&t=2916

Links to the CAA document for testing aircraft NiCad batteries.